1. Field of the Invention
This invention relates generally to the field of measuring linear distances and specifically to a slotted scale.
2. Description of the Related Art
Graduated scales used to measure distances probably predate recorded history. The precision and accuracy of the scale depend on the fineness of the graduations and the skill of the user. Inaccuracies may arise from parallax or misreading of graduations by the user. Marking every graduation on a scale clutters the scale. Therefore scales are frequently provided with unidentified graduations, thereby requiring knowledge of fractions to read the scale accurately when using the venerable English system. Even users who possess such knowledge commonly make erroneous readings or conversions of fractions.
Different scales have been developed to reduce the clutter of graduations or improve accuracy in reading the scale. Examples of scales are shown in G.B. Patent No. 15,633 to Allen, and U.S. Pat. Nos. 861,799 to Breil, 999,730 to Allen, and 2,579,664 to Gleasman. However, a need remains to further improve the accuracy and reduce the likelihood of errors resulting from inadequate knowledge of fractions or mistaken calculations. Also needed is a scale that is easier to use when measuring or marking distances.